SkiaSharp绘制可逆形状

Question

有没有一种用SkiaSharp绘制可逆形状的方法？

对于可逆的，我指的是outColor = srcColor XOR dstColor，所以当你再次绘制相同的颜色时，原来的颜色就恢复了。就像在WinForms ControlPaint.DrawReversibleFrame或(旧的) Windows FocusRects中。

我使用的是SkiaSharp 2.88.0

Answer 1

绘图时可以使用排除混合模式，例如：

// draw some random image on canvas
var bitmap = SKBitmap.Decode(@"random.jpg");
var info = new SKImageInfo(256, 256);
using var surf = SKSurface.Create(info);
var canvas = surf.Canvas;
canvas.DrawBitmap(bitmap, info.Rect);

// initialize paint with Exclusion blend mode
var paint = new SKPaint {
    Color = SKColors.Yellow,
    Style = SKPaintStyle.Fill,
    BlendMode = SKBlendMode.Exclusion
};

// draw overlapping rectangles using the paint
canvas.DrawRect(10, 10, 50, 50, paint);
canvas.DrawRect(25, 25, 50, 50, paint);

结果图像：

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